Analysis of high differential pressure in the balance pipe of high-pressure water pumps
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The high-pressure water pump used for coking in our company’s coking unit is a 10-stage centrifugal pump with an outlet pressure of 2.8 MPa. Recently, the pressure in the balance line has increased from its normal level of 0.16 MPa to 0.2 MPa. Please analyze the reasons for this phenomenon and suggest ways to address it
Is an outlet pressure of 2.8 MPa considered high? Perhaps the pressure classification levels for each device are different. Generally speaking, if the labyrinth seal on the balance disc is in good condition, the leakage from the pump’s outlet along the axis of the balance disc can be significantly reduced through the throttling effect. If the labyrinth seal on the balance disc is effective, the pressure in the balance tube will be fairly close to the pump’s inlet pressure; however, since it’s impossible for the labyrinth seal to be completely airtight, the pressure in the balance tube is slightly higher than the pump’s inlet pressure. My guess is that there is a problem with the labyrinth seal on the pump’s balance disc, which results in an inadequate throttling effect on the leaking high-pressure fluid.
There are generally two possible reasons for an increase in the pressure of the balance tube: one is an increase in the inlet pressure, and the other is excessive wear of the balancing device. Once the cause is identified, you’ll know how to deal with it.